Apparatus for generating steam



0. ENGLER APPARATUS FOR GENERATING STEAM Jan. 4, 1938. 7

Filed June 25, 193 5 6 Sheets-Sheet l lhventor: 5 Orro Eng I er.

] (fiwfi w A info/"n e vs Jan. 4, 1938. o. ENGLER APPARATUS FOR GENERATING STEAM Filed June 25, 1935 5 Sheets-Sheet 2 lnvent or: 5 .Ofro Engler 4 @M- EZQM 0. ENGLER APPARATUS FOR GENERATING STEAM Jan. 4, 1938.

Filed June 25. 1955 6 Sheets-Sheet 3 Jan. 4, 1938. o. ENGLER APPARATUS FOR GENERATING STEAM Filed June 25, 1955 6 Sheets-Sheet 4 A fie/" 7915 Jan. 4, 1938. o. ENGLER 2,104,613

APPARATUS FOR GENERATING STEAM Filed June 25, 1935 G-SheetS- Sheet 5 v I A &

Otto Enqmr Attorneys Jan. 4, 1938. Y

O. ENGLER APPARATUS FOR GENERATING STEAM Filed June 25, 1935 6 Sheets-Sheet 6 Er y mmflk m 0 8w n M 0 T, Jr w m Patented Jan. 4, 1938 UNITED STATES PATENT OFFICE 2,104,613 APPARATUS FOR GENERATING STEAM many Application June 25, 1935, Serial No. 28,366

In G

9 Claims.

The invention relates to a method and apparatus for generating steam, and particularly for the indirect generation of steam through a flowing heating medium. 1

In the past, in the indirect generation of steam by means of a fluid heating medium such as superheated steam, it has been usual to heat the heating medium at one point and then to pass it at a different point in heat exchange relation with the water to be vaporized. In other words, the absorption of heat by any part of the heating medium and the radiation of heat thereby (that is, the giving up of heat to the water to be vaporized) have taken place at different times and at different points. This alternate absorption and radiation of heat must be carried on repeatedly in order to obtain proper efiiciency in the generation of steam.

The fundamental difference between the method according to the present invention, and such earlier procedures, is that in the new process the radiation of heat to the liquid to be vaporized is combined with the supply of heat to the heating medium, so that the two steps are simultaneous. The new method of indirect steam generation by the use of a flowing heating medium consists, preferably, in supplying heat to the heating medium from an exterior source during the same period in which it is giving up heat to the liquid to be vaporized.

The invention is preferably carried out by means of a system of double walled tubes which are heated by fire or combustion gases, and which provide separate paths of flow for the liquid to be vaporized and the heating medium to move in heat exchange relation with each other. For example, the liquid to be vaporized may flow through the inner space of the'tubes and the heating medium through the annular outer space.

- The inner tube may be in the nature of a Field tube.

The principal advantage of the present in vention lies in the fact that the average temperature diiference between the heating medium and the liquid to be vaporized is greater, assuming the same maximum temperature for the heating medium, than in prior steam generating methods, in which the temperature of the heating medium drops rapidly duringthe time in which it is giving up heat to the liquid to be vaporized. As a result, with the same dimensions of heat exchange surfaces and without submitting the heat absorption surfaces for the heating medium to any higher temperatures, a greater boiler output may be obtained.

ermany June 28, 1934 The invention further contemplates an arrangement in which the greater part of the heat required for the heating and vaporization of the liquid to be vaporized, and preferably substantially all of this heat, is supplied to the heating medium when it is in heat exchange relation to the liquid. The invention is particularly applicable to arrangements in which the steam thus indirectly generated is itself used as the heating medium for vaporizing further quantities of the liquid, and is then led off to its point of consumption.

Further objects and advantages of the present invention will be more fully apparent from the following description, particularly when taken in conjunction with the accompanying drawings which form a part thereof.

In the drawings:

Fig. 1 is a vertical section, partly diagrammatic, through a steam generator embodying my invention. I

Fig. 1a is a similar view showing a modification of the heating arrangement of Fig. 1.

Fig. 2 is an enlarged cross section through the steam generating portion of the arrangement 95 shown in Fig. 1. d

Fig. 3 is an enlarged cross section substantially on the line III-III of Fig. 2.

Fig. 4 is a cross section on the line IV-IV of Fig. 3.

Fig. 5 is a cross section similar to a portion of Fig. 2 through a modified form of tube construction.

Fig. 6 is a cross section substantially on the line VIVI of Fig. 5.

Fig. 7 is a vertical section, partly diagrammatic, through a modified form of generator.

Figs. 8 and 9 are detailed views, principallyin section, of portions of the device shown in Fig. '7.

Fig. 10 is a cross section, partly diagrammatic, through a modified form of the invention particularly adapted for marine boilers.

Fig. 11 is a cross section through a part of the vaporizing system of the device shownin Fig. 10.

Fig. 12 shows in cross section, partly diagrammatic, a portion of a modified form of marine boiler. v

Fig. 13 is a section through a part of the vaporizer tubes of Fig. 12.

Fig. 14 shows, in section, a further modification of the fluid circuit portion of a further type of generator.

As shown in Fig. l, the construction includes an upper steam l, which is adapted to hold 55 7 vertical series.

ranged in the flue 5, from top to bottom, are a superheater 6, a feed water preheater 1 and an air heater 8.- These devices are merely indicated diagrammatically in the drawings. N

The loop tubes 2 consist of casings into which inner tubes, preferably constructed as, Field tubes, may extend. Thesetubes consist, for instance, of inner members or tube sections 9 and. outer members or tube sections l0 (Figs.;2 to 4),

forming therebetween an annular space 2-9; -The Field tubes extend down into thelegs of the U or loop tubes, and the closed ends of the tube sections H) are located near the ends of the legs of the-loop tubes. The bent portions or elbows 12- of the U-tubes, which have'no inner tubes passing therethrough, are reduced in cross 'sec-' tion s'o that the clear cros's section within the bends-'issubstantially the'same as the cross sec tionof the annulanspace-H outside the outer Field tube sections 10.

The Field tubes are arranged in a plurality of The ends of'the Field tubes of each'seriesare arranged in one of a set of vertical tubular casings M, which are divided by intermediatewalls 15 into waterchambers -l6 andfsteam charnbers 'lI. The inner sections 9 of the-Field tubes communicate with the water chambers l6, and the outer sections In with the steam chambers l1.- At their upper. ends the water chambers I6 of the cylinders l4 are connected by'nipples I8 with; the water space of drum Landat the lower ends by nipples IS with a water cylinder or header 20. Ascending pipes 21 extend from the upper ends of steam chambers ll of casings M to the drum l.

The outer sections In of the Field tubes are suitably secured in the 'wall of easing l4. -The inner sections 9, on the other hand, are removably secured by means of a special arrangement to be described. Adjacent the end of the tube section 9 which is arranged within the casing I4 is a washer 22, secured to the tube section, and

which fits into and closes an opening in the in-' tion l0, since the opening 24 is made large enough to permit-the washer 22 to pass through.

Thecover 23 may beheld tightly in place by means of a pressure yoke'25 which engages the cover 23 and is held. in place'by' boltsand nuts 26. The cover 23.may be alsoprovided with a flange which fits in arecess or seat in the casing 14, sothat -a suitable packing member 21 aran ed h reb t een w l. r d c a ght join t this point. 7 V t The inner tubeisection 9-is cut away between the front wall of casing I 4 and the intermediate wall I 5, so as to provide openings 28 through.

which thejwater in chamber 16. may passinto the" interior of the inner tube sections 9; The water thenflows through these sections-9 and baokthrou'gh the spaces 29 within the sections 10' to the steam chamberl 1." Within the spaces 29 the water is heated by steam flowing in the tubes 2, and is thus converted into steam.

The tubes 2 are sealed at their ends by the a provision of rings or washers 30, the ends of the tubes being bent down'around these washers and welded to the tube sections l 0. I f- Tl e heating steam or'heating'medium is taken fromdrum' I and passes through pipe 3| to a lower header32; from which it passes through pipes 33 to the lowest tubes of each of the vertical ITOWSTOE tubes 2. The tubes of each vertical row are connected together in series by suitable pipes 34, so that the heating medium passes through the various tubes successively. From the upper loop tube 2 of each series, pipes 35 extend to a steam collecting chamber 36, which is separatedfrom'the remaining space in the drum l by a shield or shell 31. Pipes 39 extend from the steam-,collectingchamber 36 to the superheater 6 and from this the steam is led ofi to a point of consumption. These pipes are preferably arranged al'ong th e top wall 38 0f the heating flues'4,5. F w

The water being supplied to-the drum lfor thefurther generation of steam may be preheated by passing'it through the feed water pre-p heater 1 and then through pipe 40 to the drum l.

' The heating steam or heating medium flowing in the spacesfl 3 of the U tubes is thus supplied with heat continuously by the flue or combustion gases passing up from combustion chamber 3. At the same time, the heating medium-is continuously giving ofi heat to the water flowing through the-Field tubes and thus generating steam which flows drum 1.- The heat is thus transmitted by the heating medium to, the water to be vaporized, at any predetermined =maximumtemperature of the heatingmedium, with a continuoushigh differenoe'of temperature; In other words, the temperature of the heating medium does not drop as it gives up its heat and-thus approach the heat of the liquid to be vaporized, which would reduce the radiation eificiency considerably for the same radiation space; but instead the'heating medium is kept at a high'temperature during the whole period in which it is giving off heat to the liquid to be vaporized. Therefore the heat exchange surfaces required for a given output of steam they be made smaller where the present invention is used; i

The ratio of the heat absorbed through the tubes 'Z by the heatin'g medium to the heat given off by the heating medium to the liquid to be vaporized may be modified-and suitably predetermined by varying the dimensions of the heating' surfaces. For instance, the'heat absorbing surface of the outer Field tube sections '10 may be increased by the provision of ribs, so that the heat absorbed by the heating medium will betransferred more rapidly to the liquid to be ,va'porized, In this. manner, the temperature of the heating medium. may be prevented from exceeding apredetermined temperature, and the temperature pf the tubes 2 which are subjected to. theheat; of; theflue gases may. be kept relawithin the tubes 2 to produce anirregular. path for the heating-medium so' that it passes through the, chamber l3 in eddies, which will further imthroughthe pipe 2| to the Y prove the transmission of heat to the liquid to be vaporized. 1

The arrangement may be modified in various fashions, in that it is not necessary to utilize all the steam' generated in the-drum I as heating medium for the generation of further steam. In order to start the generator, steam may be sup-r plied from an exterior source until steam is being generated at a suflicient rate to provide the necessary heating medium for continuous operation. However, it is also possible to force the circulation of water through the tubes and, if necessary, through the superheater until sufiicient steam is generated to permit the operation to becontinued. Steam from an external source may also be provided as the heating medium if desired.

In the embodiment shown, the saturated steam which is being used as a heating medium passes first to the lower or most highly heated of the tubes 2. This has the advantage that the steam flowing through the annular space of the lower tubes is comparatively cool, and thereby serves to cool these tubes to a certain extent and protect them from the heat of the combustion gases. The arrangement, however, may be reversed where the tubes are subjected to relatively low temperatures only, in which event it is preferable to cause the heating medium and thefiue gases to move in counter-current relation, so that the heating medium. will leave the tubes at a point of comparatively high temperature, from which it passes to its point of use as shown in Fig. 1a..

A modified form of tube structure is shown in Figs. 5 and 6. In this arrangement, instead of providing separate tubes 34 connecting the loop tubes to each other, these loop tubes are connected through the same casing which provides the water and the steam chambers. Vertical casing I4 here contains an intermediate wall I5 separating water space l6'from' steam space H, and a further separating wall 42 which separates steam space H from a heating steam chamber 43. The ends of the tubes 2 are suitably secured in the wall of casing M in communication with chamber 43. Horizontal walls 44 arranged in the chamber 43 divide the same into a plurality of spaces. These walls are arranged between the legs of each loop tube, so that the steam may flow from one tube to the next but is then forced to fiow through the tube to reach the next upper space. The heating medium thus is forced to fiow successively through the tubes 2. The upper end of the chamber 43 may be connected in any'suitable manner to the space 36 within the drum l. i

In this arrangement, the outer Field tube sections H] are also provided with flanged washers 45 secured on their ends'which fit in openings in the separating wall 42. The inner tubes 9 carry at their ends plugs or closure members 23 which fit in openings in the wall of casing |4, and are held in place by pressure yokes 46 and nuts 41. The ends of outer tube sections ID are cut away, so as to form legs 48 which rest against the washers 22 fixed on tube sections 9, the spaces between the legs 48 providing for the escape of steam from the tube sections l0 into the space H.

A further modification of the invention is shown in Fig. 7. This arrangement in general is the same as that shown in Figs. 1 to 4. However, double walled tubes 50 are provided which extend across the flue space 4 and down the'rear wall thereof below the loop tubes 2. These tubes 1 56 form a rear wall for the-combustionchamber 3. The? tubes 50 enclose inner tubes 5|, which fit within the tubes 50' and are bent jointly with the outer tubes. Inner tubes 5| are connected to the steam chambers ll of the casings M (Fig. 9) to which the outer tube sections H) of the Field tubes in the loop tubes 2 are also connected. The upper ends of outer tubes 59 are sealed off in the same manner as the ends of loop tubes 2, and connecting pipes 52 extend from outer tubes 59 to thelow est of each series of loop tubes 2.

At the lower ends, the outer tubes 50 and inner tubes 5| are connected with a cylinder 53, which is subdivided by a separating wall 54 into a steam chamber and a water chamber. Outer tubes 50 are suitably secured in the wall of cylinder 53 and communicate with the steam chamber section thereof. Inner tubes 5| engage at their lower ends with tube sections 55. Flanged washers 56 secured on tube sections 55 fit into and close openings in separating wall 54. Sections 55 als o carry plugs or closures 51 which are suitablysecured in openings in cylinder 53 by yokes 59 and nuts 60. Rings or collars 58 fit into the v aligned ends of tubes 5| and tube sections 55 and thu'sform tight connections therebetween. The parts of the tube sections 55 within the water chamber are cut away as at 63 to provide openings through which the tubes 5| may communicate with the water chamber.

A pipe 6| connects the water space of the chamber 53 with the drum I, while a pipe 62 connects the steam space of cylinder 53 with the top of the drum I so as to receive steam therefrom. The heating medium or heating steam flows through the outer spaces of the tubes 56 and then through the spaces of tubes 2 to the steam collecting chamber 36. The water to be vaporized passes first through pipe 6| to the water space of chamber 53, then through inner tubes 5| and then through chambers IT to the drum Figs. 10 and 11 show a marine boiler having in the'usual form two groups or sets of inclined tubes 66 with a combustion chamber 64 arranged therebetween. These groups of tubes communicate with a common steam drum 65. However, according to the invention, such tubes are not simple tubes, but consist of outer tubes 66 and inner Field tubes consisting of outer tube sections 68 and inner tube sections 69. The outer tubes 66 of each set form in effect a continuous tube. The straight sections of the outer tubes are connected at their lower ends by closed loops or bights, and at their upper ends adjacent the drum 65 by closures or covers 61. The Field tubes extend through the covers 67 into the straight sections of the outer tubes. The outer Field tube sections 68 are suitably secured in the wall of the drum 65, and the inner tube sections 69 also communicate with the interior of the drum. From the drum 65 the water flows downwardly in the inner tube sections 69, and the mixture'of steam and water formed by the heating rises through the outer tube sections 68 into the" cylinder 65.

The outer tube groupseach consists of a plurality of tubes connected at one end with a lower steam cylinder H and at the other end with a steam cylinder 12. Heating steam drawn from the top of drum 65 passes downwardly through pipe 13 into drums 1|. It then passes successively through the outer tubes 66 to drum 12,

from which it passes through pipe 14 to a super- "15 to the point ofconsumption."

A further modified form of. the. inventionis is receiving heat ,from,the, iire bos fl at the same time thatit isgiving; up heat to the water to be vaporized in the. Field tubes.

In the arrangement shown in Figs. 12(and 13, which is in many respectsv similar tothat of Figs. .10 and 1.1, the outer tubes 66 instead oi being connectedat their lower ends by loops or bights are connected by closures or plugs: 1'.4-".MOIQ- over, in this .form Field tubes are not used, but instead simple water tubes 11. l'lhese tubes are arranged tightly in, the plugs 61 and .16. Tubes 11 are connected at their upper ends to a drum 65, and at their lower ends to a drum l8. flwo steam chambers 19 and 80 are formed by su tame separating walls which divide them from the water space of drum 18. One end of the outer tube group 6.6 is connected by apipe 8|- with steam chamber .19,and the other end by a -pipe 82 with steamchamber 80. A pipe 13 connects drum G with steam chamber 19. s A further pipe 83 connects the water space of drum 65 with. the'wa? ter space of drum 18. From the space 80 the steam flows through pipe 14 and superheater shown in Fig. 14. 'In this construction, the heating steam afterpassing through; the tubes 2 is not ledaway to a point of consumption but is returned in a closed circuit through the hea ting' Furthermore, this steam isnottaken, from. the drum I ofthe indirectly heated gen tubes.

erator, but is drawn from a separate source. in the arrangement shown in this figure, the drum I and the. Field tube arrangement is the same as that shown in Figs. 1 and 2;;the loop tubes 2 also corresponding to those shown in "the earlier figure. -However,' the heating steam is supplied through a passage Hi0 into a steam cylinder "H from any suitable source. fThe steam fiows through a passage 102 to a pump L03 which forces it through passage IM toheader or distributing? cylinder i 05. Pipes .106 extend from header 105 to the lower tubes 2 of each vertical ,groupjThe heating steam passes through the loop tubes 2 and then is returned through tubes I01 tocylinder Illl. In thisform also, as will be noticed, the heating steam mere- 1y serves as a heating mediurmand substantially all the heat actually'supplied for generating steam is received from the flue. gases, theheating steam being merely an intermediary for such heat. 7 While the flow. of water to bevaporized in the construction disclosed takes place through gravity and throughthe generation; ofsteam, it is obvious that such flow could be caused in any other suitable manner, as for instance. by the provision of aiwater circulating punish tween the steam, drum and the openings of the inner Field tube sections. I .While I have described herein several. embodiments ofomy inventioml'wish it toibeunderstood that I do not intend to limit myself e kcept within the scope of the'appended. claims' Iclaim: V '1 j" 1. A steam generator. comprising a steam drum, a plurality of Field tubes havinginner'and outer tube sections, means for conducting liquid fromsaid to the inner tube sections, means for conducting; steam from the. outer tube 'sea-v tions to. the drum, a plurality' of o'ther tubes surrounding said Field tubes, means to conduct steam from saiddrumto said, second tube s and from said second web ites be use, and

1.5 Queens wh n an swans iii s;

2 A steam generamor comprising a steam dru'm, a plurality of Field't'ubes having inner and a plurality of 'double wall'ed tubes, means to conductlliquid from said drum, to the inner spaces oithe tubes,'means for passing off the steam genera-ted infs'aid inner spaces, means to conduct steam from. said drum to' the outer spacesof said tubes, said outer spaces of said tube'sfbeing' connected in series, and said' last conducting'means' being connected to the outer space of that tube which is exposed tothe highest temperature, and means to heat said tubes.

4L 'A steam generator comprising a steam drum, a. plurality of Field tubes having inner and outer tube. sections, means, for conducting liquid from said. drum to the inner' tube sections, means for conductingsteamiromfthe' outer'tubc "sections ftofthefdrum, a. plurality offsecond, tubes surrounding "said Field tubes, said second 'tub'es beingconnected'in series," means to conduct steam from said drum to said second tubes and from said second tubes to a point of use, and means to. heat. saidjsecond' tubes.

p 5'. 'A steam'generat'or comprising a. steam drum, a, plurality 01'. Field, tubes having inner and outer tube. sections, means for conducting liquid from said to. the irine'r'tube-sections, means for conducting steam from the outer tube sections to thefdrum, -a. pluralityfof second tubes surrounding said Field tubes, means to conduct steam from, said drum to. said second tubes and 'fromsaid second tubes, ma point of use, said last conducting means from the drum being con nected to. that, onefof said second tubes which is exposed to. the highest temperature, and means to heat'saidsecoridf tubes.

l6. An/ apparatus for the indirect generation of steam 3 comprising "a combustion chamber and steam. generating means. said means consisting -of asystem having a steam drum, a plurality of steam generating double-walled tubes located substantially entirely within said, combustion chamber and forming substantially the whole of and a steam generating system, said system consistirig entirely of a steam drum, a plurality of (double-walled tubes. located substantially entirely withinisaidcombustion chamber and formins substantially thelwholel of the. steam generating'mea'ns,' to conduct liquid from said I 512%. 1 ,i id t e n w m conduct steam generated in said inner spaces to said drum, means to conduct steam to the outer spaces of said tubes, and means to heat the outside of the tubes.

9. A steam generator for the indirect generation of steam consisting of a steam drum, a plurality of double-walled tubes forming substantially the whole of the steam generating means, means to conduct water to the inner spaces of said tubes, means to conduct steam generated in the inner spaces to said drum, means to conduct steam to the outer spaces of said tubes, and 5 means to heat said tubes.

OTTO ENGLER. 

